Medical injection systems and pumps

ABSTRACT

According to preferred embodiments and methods of the present disclosure, a medical injection system employs a single pump for the injection of multiple fluids, rather than employing a pump for each type of fluid, for example, like the prior art system described above. Embodiments of pumps disclosed herein preferably include a disposable pump cartridge configured to be contained within a hull of a medical injection system, wherein the hull may be formed when a pressure plate member is closed against a base plate; and, when the pressure plate member is opened with respect to the base plate, the disposable pump cartridge may be removed and replaced.

TECHNICAL FIELD

Embodiments of the present disclosure pertain to medical injectionsystems and more particularly to the pumps employed therein.

BACKGROUND

FIG. 1 is a perspective view of an exemplary medical injection system100 (the ACIST CVO system) for delivering a contrast agent into apatient's vascular system for medical imaging. FIG. 1 illustrates afirst fluid reservoir 132 for supplying a syringe-type positivedisplacement pump of a pressurizing unit 130, via a fill tubing line27-F, and an injection tubing line 27-I coupled to unit 130 forinjection of, for example, a radiopaque contrast agent, into a patient'svascular system via an inserted catheter (not shown), for example,coupled to a patient tubing line 122 at a connector 120 thereof. FIG. 1further illustrates a second fluid reservoir 138 from which a diluent,such as saline, is drawn by a peristaltic pump 106 through yet anothertubing line 128 that feeds into tubing line 122. A manifold valve 124and associated sensor 114 control the flow of fluids into tubing line122, from pressurizing unit 130 and from tubing line 128.

SUMMARY

According to preferred embodiments and methods of the presentdisclosure, a medical injection system employs a single pump for theinjection of multiple fluids, rather than employing a pump for each typeof fluid, for example, like the prior art system described above.Embodiments of pumps disclosed herein preferably include a disposablepump cartridge configured to be contained within a hull of a medicalinjection system, wherein the hull may be formed when a pressure platemember is closed against a base plate; and, when the pressure platemember is opened with respect to the base plate, the disposable pumpcartridge may be removed and replaced.

The disposable pump cartridge preferably includes a shell and a piston,wherein the piston is contained within an inner surface of the shell andincludes a bore that is adapted to be operably engaged by a drive memberand a fixed gear of the injection system; each of the fixed gear and thedrive member are inserted through a corresponding opening formed throughthe shell, when the cartridge is contained within the hull. The drivemember is preferably coupled to a free end of a motor drive shaft, whichextends through the base plate, and the fixed gear is preferably mountedto the pressure plate member. According to some preferred embodiments,the disposable pump cartridge is configured to function as aLimaçon-to-Limaçon machine, wherein sliding and rotational motion of thepiston is driven by an eccentric drive member of the injection system tocreate expanding and contracting cavities during pump operation. Thepiston further includes a pressure seal that extends thereover and isconfigured to be in sliding and sealing engagement with the innersurface of the shell to seal the expanding and contracting cavities fromone another within the shell, and to seal the cavities from the firstand second openings of the shell. Fill and injection ports of the shellare preferably located at opposite ends of a long axis of the piston,when the piston is in a position where the contracting cavity is at amaximum volume and the expanding cavity is at a minimum volume.

According to some embodiments, each of the fill and injection portsincludes a channel and one or more apertures formed in the inner surfaceof a perimeter wall of the shell, wherein each channel extends from thecorresponding one or more apertures to a corresponding opening inoutside the shell. When the disposable cartridge is contained in thehull of the system, the fill and injection ports preferably extendthrough openings in the pressure plate member, and each has a fittingoutside the hull for coupling to a fill and an injection tubing line,respectively, of the system.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular methods andembodiments of the present disclosure and, therefore, do not limit thescope. The drawings are not to scale (unless so stated) and are intendedfor use in conjunction with the explanations in the following detaileddescription. Methods and embodiments will hereinafter be described inconjunction with the appended drawings, wherein like numerals denotelike elements, and:

FIG. 1 is a perspective view of an exemplary prior art medical injectionsystem;

FIG. 2A is a schematic depicting a medical injection system, accordingto some embodiments of the present disclosure;

FIG. 2B is an exploded perspective view of a disposable pump cartridgethat may be employed by the system depicted in FIG. 2A, according tosome embodiments;

FIG. 2C is a perspective view of a pressure seal that may beincorporated in the disposable pump cartridge of FIG. 2B, according tosome embodiments;

FIG. 2D is an exploded perspective view of a portion of a medicalinjection system, according to some embodiments;

FIG. 3A is a cut-away plan view of an interior of a disposable pumpcartridge, according to some embodiments;

FIGS. 3B-C are schematics depicting exemplary expanding and contractingcavities of the pump cartridge;

FIG. 4A is a cross-section view through section line A-A of FIG. 3A,when the disposable pump cartridge is assembled into a hull of thesystem of FIG. 4A, according to some embodiments;

FIG. 4B is a cross-section view through section line B-B of FIG. 3A,according to some embodiments; and

FIG. 4C is an enlarged detail of a portion of a pump cartridge,according to some embodiments.

DETAILED DESCRIPTION

The following detailed description is exemplary in nature and is notintended to limit the scope, applicability, or configuration of thedisclosure in any way. Rather, the following description providespractical illustrations for implementing exemplary methods andembodiments. Examples of constructions, materials and dimensions areprovided for selected elements, and all other elements employ that whichis known to those skilled in the art. Those skilled in the art willrecognize that many of the examples provided have suitable alternativesthat can be utilized.

FIG. 2A is a schematic depicting a medical injection system 200,according to some embodiments. FIG. 2A illustrates system 200 includinga single pump 230, which is coupled between a fill tubing line 217F andan injection tubing line 217I, and which is formed by a hull 25 and adisposable pump cartridge 23 (shown with dashed lines) containedtherein. Hull 25 may be formed by a base plate 42 and a pressure platemember 41 that may be opened and closed with respect to base plate 42 toremove and install disposable pump cartridges 23. FIG. 2A furtherillustrates system 200 including a plurality of fluid reservoirs, forexample, two types of contrast agent reservoirs 232A, 232B and a salinereservoir 238, connected to fill tubing line 217F via a manifoldassembly 224 (i.e. an inlet stop cock valve) that couples each reservoir232A, 232B, 238 to pump 230. According to the illustrated embodiment,manifold assembly 224 is controllable to select one of reservoirs 232A,232B, 238 for filling pump 230 and, once primed, pump 230 is operablesimultaneously fill and inject fluid from the selected reservoir.

FIG. 2A shows each of fill tubing line 217F and injection tubing line217I preferably extending over a limited length, for example, less thanapproximately 25 mm, and injection tubing line 217I transitioning into adual lumen line 227I wherein a first lumen is dedicated to contrastagent and a second lumen to saline. Dual lumen line 227I is showncoupled to injection line 217I via a stop-cock valve 274 that can beswitched back and forth between the lumens of line 227I, depending onthe type of fluid that is being pumped, saline or contrast agent, so asto prevent excessive waste of contrast agent. FIG. 2A furtherillustrates a y-connector 265 coupling dual lumen line 227I to a patientline 269. According to the illustrated embodiment, y-connector 265preferably includes a check valve to prevent backflow into dual lumenline 227I. Furthermore, when a pressure transducer is incorporated inline 269 for patient blood pressure monitoring, the check valve helps toimprove hemodynamic signal quality by isolating line 269 from line 227I.

FIG. 2B is an exploded perspective view of disposable pump cartridge 23,according to some embodiments. FIG. 2B illustrates cartridge 23including a shell that has a first sidewall SW1, a second sidewall SW2and a perimeter wall PW, and a piston 28 configured to be containedwithin the shell and moved therein to form two dynamically expanding andcontracting cavities for drawing in and injecting out, respectively,fluid from any of the aforementioned fluid reservoirs 232A, 232B, 238.With further reference to FIG. 2B, when the shell contains piston 28, afirst side 281 of piston 28 extends adjacent to an inner surface 211 offirst sidewall SW1, a second side 282 of piston 28 extends adjacent toan inner surface 221 of second sidewall SW2, and an outer perimeter edge83 of piston 28 extends adjacent to an inner surface 251 of perimeterwall PW. Furthermore an inner perimeter edge of piston 28, which forms abore 810 through piston 28, includes a first portion 811, located inproximity to a first opening 201 formed through first sidewall SW1 ofshell, and a second portion 812 located in proximity to a second opening202 formed through second sidewall SW2 of shell. According to theillustrated embodiment, first opening 201 allows insertion therethroughof a fixed gear 340 (FIGS. 2D, 4A) to mate with first portion 812 of theinner perimeter edge of piston 28, and second opening 202 allowsinsertion therethrough of a drive member 442 (FIGS. 2D, 4A) to mate withsecond portion 812 of the inner perimeter edge, for the operation ofpump 230, which is described below.

FIG. 2D is an exploded perspective view of a portion of pump 230,wherein fixed gear 340 may be seen mounted on pressure plate member 41,and drive member 442, which is coupled to a free end of a motor driveshaft 441, is illustrated with dashed lines on a side of base plate 42that faces second opening 202 of the shell of pump cartridge 23 for theaforementioned engagement with piston 28. It should be noted thatsuitable bearing supports, known to those skilled in the art ofmechanical design, may be employed to support drive shaft 441 as itpasses through base plate 41 and to support drive member 442 mounted onthe free end of drive shaft 441. With reference to FIGS. 2A and 2D, baseplate 42 may be part of a housing 24 that contains the motor from whichdrive shaft 441 extends, and pressure plate member 41 is coupled to baseplate 42, for example, by a hinge and pull action toggle clamp or a pullaction cam clamp to form hull 25 that contains pump cartridge 23 andholds pressure during pump operation, and to allow opening and closingof hull 25 for the replacement of disposable pump cartridge 23, forexample, after the completion of each imaging procedure. According topreferred embodiments, drive member 442 is a roller bearing mountedeccentric adapted for a toothless engagement with second portion 812 ofthe inner perimeter edge of piston 28 that facilitates alignment whendisposable cartridge 23 is assembled into hull 25.

According to an exemplary embodiment, hull 25 may be formed of stainlesssteel, while piston 28 and first and second sidewalls SW1, SW2 andperimeter wall PW of the shell are preferably formed, for example byinjection molding, from a polycarbonate material, such as APEC® 1745.Each wall of the shell may have a nominal thickness of betweenapproximately 0.070 inch and approximately 0.080 inch, which ispreferably uniform along both sidewalls SW1, SW2 and perimeter wall PW,for example, to avoid sink discontinuities from forming during injectionmolding of the shell. According to the illustrated embodiment, secondsidewall SW2 of shell may be formed independently of first sidewall SW1and perimeter wall PW and then attached about a facing edge 27 ofperimeter wall PW, for example by tongue-in-groove engagement andultrasonic welding or adhesive bonding, wherein the adhesive may be acyanoacrylate or a UV cure adhesive, or any suitable adhesive known inthe art.

With further reference to FIG. 2B, piston 28 includes a pressure seal288 formed thereover for sliding and sealing engagement with each of theaforementioned inner surfaces of the shell. FIG. 2C is a perspectiveview of pressure seal 288 separated from piston 28. FIGS. 2B-Cillustrate pressure seal 288 including a first seal ring portion SR1that extends about a perimeter of first side 281 of piston 28, a secondseal ring portion SR2 that extends about a perimeter of second side 282of piston 28, and a pair of seal strip portions SS that extend betweenfirst and second seal ring portions SR1, SR2 and along outer perimeteredge 83 of piston 28 opposite one another at either end of a long axisof piston 28. The seal rings and strips of pressure seal 288 arepreferably integrally over-molded onto the piston; and, according to anexemplary embodiment, are formed of 917CK silicone rubber (MinnesotaRubber & Plastics of Minneapolis, Minn.) having a hardness of 75+5 on aShore A scale. According to the illustrated embodiment, pressure seal288 engages with the inner surfaces of the shell to seal expanding andcontracting cavities, which are created by the movement of piston 28within the shell, from one another and from openings 201, 202.

According to some preferred embodiments, disposable pump cartridge 23 isconfigured to function as a Limaçon-to-Limaçon machine, wherein drivemember 442 eccentrically engages with second portion 812 of the innerperimeter edge of piston 28 to cause a sliding and rotational motionthereof, which creates expanding and contracting cavities during pumpoperation. FIG. 3A is a cut-away plan view of an interior of disposablepump cartridge 23 in which fixed gear 340 is shown engaged with firstportion 811 of the inner perimeter edge of the piston 28; and FIGS. 3B-Care schematics showing subsequent positions of piston 28, relative tofixed gear 340 and the shell, as moved by drive member 442—sliding perarrow S and rotating per arrow R (FIG. 3A), to create an expandingcavity E and a contracting cavity C.

With reference to FIG. 3A, a profile of inner surface 251 of perimeterwall PW of the shell conforms to a shape defined by a Limaçon curve inan X-axis, Y-axis coordinate system, wherein the Limaçon is traced byend points of a cord that extends along the X-axis, through the originof the X-Y coordinate system (over a length equal to twice the lengthL), and is divided in half by the origin. The Limaçon is represented bythe following Cartesian equations:X=r×sin(2θ)+L×cos(θ), andY=r−r×cos(2θ)+L×sin(θ);wherein r is a radius of a base circle having a perimeter along which acenter point of the cord slides as the end points of the cord rotateabout the center point of the cord to trace the Limaçon; r divided by Lis less than or equal to 0.25; and θ extends from 0 to 2π. FIG. 3Afurther illustrates the long axis of piston 28 being approximately thelength of the cord (2×L) and having a shape symmetrical across the cord,wherein the curvature of the shape on each side of the cord alsoconforms to the Limaçon represented by the above equations, but whereinθ extends from π to 2π. Such a Limaçon-to-Limaçon machine is furtherdetailed by Ibrahim A. Sultan in Profiling Rotors for Limaçon-to-LimaçonCompression-Expansion Machines, Journal of Mechanical Design, July 2006,Volume 128, pp. 787-793, © 2006 by ASME, which is hereby incorporated byreference. With further reference to FIG. 3A, an injection port IP islocated at one end of the long axis of piston 28, and a fill port FP islocated at the opposite end of the long axis of piston 28, when piston28 is at the illustrated dead center position.

With reference to FIG. 3B, piston 28 has been moved counter-clockwisefrom the dead center position, which is shown in FIG. 3A, to a positionat which contracting cavity C is in fluid communication with injectionport IP and is beginning to be compressed for injection of fluid, perarrow I, while expanding cavity E is in fluid communication with fillport FP and beginning to be enlarged to draw in fluid, per arrow F. FIG.3C illustrates a subsequent position of piston 28, having been movedthrough the position shown with dotted lines in FIG. 3B, at whichcontracting cavity C is approaching a minimum volume and expandingcavity E is approaching a maximum volume at which it becomes thecontracting cavity C of FIG. 3A. The maximum volume of contractingcavity C may be between approximately 2 cubic centimeters andapproximately 10 cubic centimeters, wherein a volume closer to 2 cubiccentimeters may be preferred for less stress on the shell and piston 28,and in order reduce a waste of fluid when switching from one type toanother, for example, from a contrast agent 232A or 232B to saline 238(FIG. 2A); yet, a volume closer to 10 cubic centimeters will allow thepiston to move more slowly thereby reducing wear on pressure seal 288and decreasing the possibility of fluid cavitation. It should be notedthat the volume may be modified by changing the radius r and length L(FIG. 3A) and/or by modifying a height H of inner surface 251 ofperimeter wall PW along with a corresponding increase in a thickness tof piston 28 (FIG. 4C).

Turning now to FIGS. 4A-B, which are cross-section views through sectionlines A-A and B-B, respectively, engagement of the parts of pump 230 maybe seen. FIG. 4A illustrates pressure plate member 41 in a closedposition with respect to base plate 42 after disposable pump cartridge23 has been mounted on eccentric drive member 442, by insertion of drivemember 442 in through opening 202 of second sidewall SW2 of the shell toengage with second portion 812 of the inner perimeter edge of piston 28.When pressure plate member 41 is closed with respect to base plate 42,fixed gear 340 passes through opening 201 of first sidewall SW1 of theshell to engage with the toothed first portion 811 of the innerperimeter edge of piston 28, wherein the engagement of gear 340 andfirst portion 811 keep piston 28 ‘on track’ to slide about radius r(FIG. 3A) as drive member 442 rotates piston 28. FIGS. 4A-B furtherillustrate the engagement of first and second seal ring portions SR1,SR2 of pressure seal 288 extending outward from piston 28 to engage withinner surfaces 211, 221 of first and second shell sidewalls SW1, SW2.According to FIG. 4B, in some embodiments, each of seal rings SR1, SR2is seated in a groove formed at the intersection of the correspondingone of the first and second sides 281, 282 of piston 28 with outerperimeter edge 83 of piston 28, and a cross-section of each of sealrings SR1, SR2 is preferably oval. The cross-section of seal strips SSmay also be oval-shaped, and each may be seated in a correspondinggroove extending along outer perimeter edge 83 between first and secondsides 281, 282. According to some embodiments each of seal rings SR1,SR2 and seal strips SS extends out from the corresponding groove tocontact with corresponding inner surfaces of the shell with a standardcompression of approximately 20%, and pressure seal 288 preferably formsthe only interface between piston 28 and the inner surfaces of theshell. According to a preferred embodiment, wherein piston 28 is formedfrom the aforementioned polycarbonate and pressure seal 288 of theaforementioned silicone rubber, pressure seal 288 is directly bonded topiston 28, for example, within the above-described grooves, during theprocess of over-molding seal 288 onto piston 28.

FIG. 4A further illustrates injection port IP and fill port FP,according to some preferred embodiments, wherein each includes a channel43 that extends from a corresponding one or more apertures 40,preferably a plurality of apertures, formed in inner surface 251 (FIG.2B) of perimeter wall PW, such that the above-described fluidcommunication between each port IP, FP and the corresponding cavity C, Eis provided by the corresponding one or more apertures 40. According tothe illustrated embodiment, each channel 43 further extends throughfirst sidewall SW1 of the shell and through a corresponding openingformed through pressure plate member 41. With further reference to FIG.4A, a first fitting 431 is coupled to channel 43 of injection port IPand a second fitting 432 is coupled to channel 43 of fill port FP,wherein first fitting 431 is adapted to couple with injection tubingline 217I and second fitting 432 with fill tubing line 217F outside hull25 (FIG. 2A). Fittings 431, 432 are preferably different types to assistin the proper connection of injection tubing lines 217F and 217I.

FIG. 4C is an enlarged detail view of one of channels 43 and thecorresponding plurality of apertures 40, according to some embodiments,wherein each aperture has an oval shape with chamfered edges to preventdamage to seal strips SS as each end of the long axis of piston 28 movespast apertures 40. Channel 43 of fill port FP is preferably larger thanthat of injection port IP, and, according to an exemplary embodiment, adiameter of channel 43 for fill port FP is approximately 8 millimetersand each of the corresponding plurality of apertures 40 is approximately2 millimeters by 6 millimeters, while a diameter of channel 43 forinjection port IP is approximately 3 millimeters and each of thecorresponding plurality of apertures is approximately 1 millimeter by 2millimeters.

In the foregoing detailed description, disclosure subject matter hasbeen described with reference to specific embodiments. However, it maybe appreciated that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theappended claims.

The invention claimed is:
 1. A disposable pump cartridge for a medicalinjection system, the cartridge comprising: a shell including a firstsidewall, a second sidewall opposite the first sidewall, a perimeterwall extending between the first and second sidewalls, a first openingextending through the first sidewall, a second opening extending throughthe second sidewall, a fill port, and an injection port, the ports beingformed in the perimeter wall, and the shell being configured for thecartridge to be removably assemblable into a hull of the injectionsystem such that the first opening, the second opening, the fill port,and the injection port each align with corresponding hull openings; apiston contained within the shell and including a first side, a secondside opposite the first side, an outer perimeter edge extending from thefirst side to the second side, and an inner perimeter edge forming abore of the piston that extends from the first side to the second side,the inner perimeter edge including a first portion and a second portion,the first portion being configured to engage with a fixed gear of theinjection system, the first opening of the shell allowing insertion ofthe gear through the first opening of the shell and through thecorresponding hull opening for the engagement, and the second portionbeing configured to engage with a drive member of the injection system,the second opening of the shell allowing insertion of the drive memberthrough the second opening of the shell and through the correspondinghull opening for the engagement with the second portion of the pistoninner perimeter edge; and a pressure seal including a first seal ring, asecond seal ring, a first seal strip, and a second seal strip, the firstseal ring extending about a perimeter of the first side of the piston,in proximity to the outer perimeter edge, the second seal ring extendingabout a perimeter of the second side of the piston, in proximity to theouter perimeter edge, the first seal strip extending from the first sealring to the second seal ring along the outer perimeter edge, and thesecond seal strip extending from the first seal ring to the second sealring along the outer perimeter edge and being generally opposite thefirst seal strip; wherein, when the disposable pump cartridge isassembled into the hull of the injection system, the fill port of theshell and a fill tubing line of the injection system are coupledtogether through the corresponding hull opening, and the injection portof the shell and an injection tubing line of the injection system arecoupled together through the corresponding hull opening; wherein, whenthe fixed gear and the drive member of the injection system engage withthe piston to move the piston within the shell, an expanding cavity anda contracting cavity are formed within the shell, the expanding cavitybeing in fluid communication with the fill port, and the contractingcavity being in fluid communication with the injection port; and thefirst seal ring is in sliding and sealing engagement with an innersurface of the first sidewall of the shell to seal the expanding andcontracting cavities from one another and from the first opening of theshell, the second seal ring is in sliding and sealing engagement with aninner surface of the second sidewall of the shell to seal the expandingand contracting cavities from one another and from the second opening ofthe shell, and the first and second seal strips are in sliding andsealing engagement with an inner surface of the perimeter wall of theshell to seal the expanding and contracting cavities from one another.2. The cartridge of claim 1, wherein a profile of the inner surface ofthe perimeter wall of the shell conforms to a shape defined by a Limaçoncurve.
 3. The cartridge of claim 2, wherein the fill and injection portsof the shell are located at opposite ends of a long axis of the pistonwhen the piston is in a position such that the contracting cavity is ata maximum volume and the expanding cavity is at a minimum volume.
 4. Thecartridge of claim 1, wherein the seal rings and seal strips of thepiston are integrally formed as a pressure seal that is over-molded ontothe piston.
 5. The cartridge of claim 1, wherein each of the fill andinjection ports includes a channel and one or more apertures formed inthe inner surface of the perimeter wall of the shell, each channelextending along the perimeter wall, between the first and secondsidewalls of the shell, and from the corresponding one or more aperturesto a corresponding opening outside the shell.
 6. The cartridge of claim5, further comprising a fitting attached to each of the fill andinjection ports in proximity to the corresponding opening, each fittingbeing configured for engagement of a tubing line therewith.
 7. Thecartridge of claim 5, wherein the channel and the one or more aperturesof the fill port are larger than the channel and the one or moreapertures of the injection port.
 8. The cartridge of claim 2, whereinthe seal rings and seal strips of the piston are integrally formed as apressure seal that is over-molded onto the piston.
 9. The cartridge ofclaim 2, wherein each of the fill and injection ports includes a channeland one or more apertures formed in the inner surface of the perimeterwall of the shell, each channel extending along the perimeter wall,between the first and second sidewalls of the shell, and from thecorresponding one or more apertures to a corresponding opening outsidethe shell.
 10. The cartridge of claim 3, wherein the seal rings and sealstrips of the piston are integrally formed as a pressure seal that isover-molded onto the piston.
 11. The cartridge of claim 3, wherein eachof the fill and injection ports includes a channel and one or moreapertures formed in the inner surface of the perimeter wall of theshell, each channel extending along the perimeter wall, between thefirst and second sidewalls of the shell, and from the corresponding oneor more apertures to a corresponding opening outside the shell.
 12. Thecartridge of claim 4, wherein each of the fill and injection portsincludes a channel and one or more apertures formed in the inner surfaceof the perimeter wall of the shell, each channel extending along theperimeter wall, between the first and second sidewalls of the shell, andfrom the corresponding one or more apertures to a corresponding openingoutside the shell.
 13. The cartridge of claim 6, wherein the channel andthe one or more apertures of the fill port are larger than the channeland the one or more apertures of the injection port.